Apparatus for the top separation of nitotoluene



Feb. 8, 1949. H, CARL. 2,461,141

APPARATUS FOR THE TOP SEPARATION OF NITROTOLUENE Original Filed Jan. 2'7, 1943 2 Sheets-Shep: 1

Figure I M o rvin H. Corl INVENTOR ATTORN Y Feb. 3, 1949. H L 2,461,141

I APPARATUS FOR THETOP SEPARATION OF NITROTOLUENE Original Filed Jan. 27, 1943 i I 2 Sheets-Sheet 2 1 58 -III E 3 26 mnl 111 :H H: 1 1" m b" i B7 26 22 Figure H Figure EZ Marvin H Corl INVENTOR ATTOR N EY Patented Feb. 8, 1949 APPARATUS FOR'THE TOP SEPARATION OF NITROTOLUENE Marvin H. can, St. Louis, Mo., assignor to Atlas Powder Company, tion of Delaware Wilmington, Del., acorpora- Original application January 27, 1943, Serial No.

473,712. Divided and this application February 9, 1945, Serial No. 577,119 a This application relates to the preparation of nitrotoluene;

An object of the invention is the provision of an'improved apparatus for the'separation of pi trotoluene from nitrating liquors.

Nitrotoluenes are usually prepared by treating toluene with a .nitrating mixture made up of concentrated nitric and sulfuric acids. When trinitrotoluene is to be prepared the reaction is often performed in a plurality of stages, usually three, a first stage-in which toluene is nitrated to mononitrotoluene, a second stage in which mononitrotoluene is nitrated to dinitrotoluene, and a third stage in which dinitrotoluene is nitrated to trinitrotoluene. In each of these nitrations the toluene, or lower nitrotoluene, and nitrating acids'are usually mixed together in a reaction kettle suitably provided with means for maintaining the reaction mixture at desired temperatures. After the reaction has ceased, the reaction mixture is allowed to settle whereupon the nitrotoluene produced'separates from the spent nitrating mixture and floats on top of it, v

' ,According to the present invention nitrotoluene is separated from the spent acids in a nitrating process by means of a top separation.

The 'invention'inay'be more fully understood by reference to the accompanying drawings which show one embodiment of apparatus suitable for performing the invention and in which:

. Figure 1 is a diagrammatic view. of a nitrating kettle witha separating device of the present invention attached;

Figure 2 is a detailed view of a portion of the separating means shown in Figure 1;

Figure 3 is a detailed view of the lower portion of the separating means shown in Figure 1; and

Figure 4 is a sectional view taken along line A-A on Figure 3.

As shown in the drawings a nitrating kettle I is equipped with inlet pipe I 2 containing valve l4 and inlet pipe I6 containing valve l8. Inlet pipe l2 may be used for the introduction of the nitrating mixture, and inlet pipe 16 may be used for the introduction of toluene or lower nitrotoluene. Kettle I0 is further equipped with removable plate 20 for access to it. Through the top of nitration kettle l0 extends pipe 22 which carries cup 24 around its base. Pipe 22 is so constructed that its end portion containing cup 24 may be placed at various heights in kettle 16. This is accomplished by permitting it to slide up and down over and outside of fixed pipe 26. Pipe 22 is supported by means of a chain 28 which runs over pulleys 30 and 32 to a counterweight 1 Claim. (01. 23485) 34. In operation toluene and a nitrating mixtoluene floats on top of the heavier spent acid mixture. The two layers are shown-at 35. and

31. Then pipe 22 is let down into kettle l6 and cup 24 is,immersed. Suction is then applied to line 26 and the nitrotoluene is drawn ofi. The

" depth to which cup 24 should be sunk may be determined by removing plate 26 at the top of the tank, thieving a sample fromthe kettle, and determining the depth of the nitrotoluene layer.

By thieving a sample from the tank is meant inserting an open tube, preferably made of glass;

straight down into the tank, stopping the top end of the'tube, and withdrawing it. The depth of nitrotoluene in the tube is then the same as I the'depth of nitrotoluene in the kettle, and the proper depth to which the cup 24 may be dropped to draw off only nitrotoluene is in that way determined. p

The sliding ofpipe 22 over pipe 26and the manner in which oup.24' is afiixed to pipe 22 appear best in Figure 3. Pipe 22 is threaded on the outsideof its lower end. Threaded sleeve-36 is screwed onto the threaded end of pipe 22. Aifixed to sleeve 36 are platesSli, see Figure 4,

' which support cup 24. Pipe 22 has aflixed at itsupper end sleeve 46 and sleeve 46 is in turn fixed to flange 42. Inside of sleeve 46 slips pipe 44 which is made of the same size as pipe 22. Sleeve I 44 is fixed to flange 4'6. Flanges 46 and 42 are bolted together .by means of bolts 48 and 56 and nuts 52 and 54. Suitable packing material 55 may be inserted inside of sleeve 40. Inside of pipe 22 is pipe 26 which fits snugly therein and extends downno farther than the greatest height to which it is desired to bring cup 24. Sleeve 40, pipe 44 and flanges 46 and 42 comprise a stufling box for preventing leakage between pipes 22 and 26. It may be seen that pipe 22 and the stuffing box assembly may be slid up and down outside of pipe 26. An arrangement, shown in detail, in Figure 2 is provided for adjusting the depth of cup 24 and pipe 22. Aflixed to pipe 22 so that it extends above flange 46 is straight plate 56.

Guide 51 is fastened to fixed pipe 26 and guide plate 56. Plate 56 is slotted horizontally at intervals along its length to provide a ratchet as represented at 58. Afiixed in operative relation with slotted plate 56 is toothed pinion 60. Pinion 60 is keyed to shaft 62, and shaft 62 and pinion 64 may be turned by means of'handwheel 64. Shaft 62 maybe supported in any convenient manner so that pinion 60 will be in operative relation with ratcheted plate 56. As shown in the drawings shaft 62 is supported by brackets 56 and 68 which are attached to flangesof an elbow on pipe 26. Also afiixed to a flange on rigid pipe 26 is a pointer 70. Plate 56 bears graduations placed thereon so that the depth of cup 24 in.

kettle I may be read directly by means of pointer 10. Plate 56 is conveniently counterweighted by means of chain 28 and counterweight 34, Figure 1. When it is desired to raise or lower pipe 26 in kettle I 0 it is only necessary to turn handwheel 64 which through shaft 62 turns pinion 60 which drives ratcheted plate 56 so as to pull pipe 26 up or let it down inaccordance; with the direction in which handwheel 64 is turned.

It will be noticed that by the meansshown, very close control is had as to the depth which cup 24 is immersed into kettle 10.. Cup Zlmay, therefore, be lowered until itstop surface is barely above theinterface between nitrotoluene and spent acid. Theconstruction of cup 24 around pipe 26 may be seen to be such that when suction is applied to pipe 26, liquid is drawn in. a downward direction into cup 24 and then up pipe 26. In this way there is practically no tendency for waste acid to be drawninto pipe 26- when cup 24 is near the interface. and a relatively complete separation of nitrotoluene and spent acid may be obtained.

In operation, during the main reaction, pipe 22* carrying cup 24 will usually be lifted high in tank 24 so as to be out of the reaction mixture. After the reaction is completed, it will often be found that nitrotolueneand waste acid separate somewhat slowly. A top layer ofnitrotoluene and a bottom layer of waste acid may be separated by a considerable space in whichan emulsion of nitrotoluene and waste acid is present. This emulsion breaks as time passes, and. the middle:

layer disappears. It is often convenient in the performance of the present invention to lower the pipe 22 slowly while suction. is being applied through pipe 26 into the nitrotoluene layer in kettle before separation is completed. In this manner the first formed nitrotoluene may be.

withdrawn almost as rapidly as it separates from the waste acid, and as more nitrotoluene forms pipe 22- maybe lowered until most of" the nitrotolnene has been removed even before a complete separation has been obtained. After the removal of the nitrotoluene the spent acid may be fortified in kettle H) with further acid for use in another nitration process in the same or another kettle. If it is desired to remove spent acid or the fortified acid from the kettle, this usually be most conveniently accomplished by letting it out through exit pipe 12 and valve 14.

This application is a division of my copending application Serial Number 473,712 filed January 27, 1943 now Patent No. 2,383,707, issued August 28, 1945.

What'is claimed is:

Apparatus. for the separation of nitrotoluene from spent nitrating mixtures which comprises a nitrating; kettle, a movable pipe extending down into said kettle, said movable pipe adapted to slide in telescoping relation over a fixed pipe, a ratchet connected to said movable pipe and outside said tank, a rotatable pinion in operative relation with said ratchet to raise and lower said movable pipe in said tank, counterbalancing means supporting said movable pipe independentl'y of said fixed pipe, a cup enclosing and attached to the lower end of said movable pipe the lip of said cup lying in one horizontal plane, and the sides of'said cup beingspaced from said movable pipe, whereby liquid flowing into said movable pipe must reverse its direction, and gauge means to indicate the height of. said cup in said tank.

MARVIN H. CARL.

REFERENCES CITED The following references. are of record in the. file of this patent:

UNITED STATES PATENTS- Number Name Date 33,736 Elliot Nov. 19,1861. 466,336 Franklin Jan. 5, 1892 872,232 Harbert Nov. 26,1907 929,250. Reynolds July 27, 1909 1,183,635 Dougans May 16, 1916 1,494,737 Cournyer May 20*, 1924. 1,584,550 Kelloggv May 11,1926 2,015,850 Harrod Oct; 1, 1935' 2,254,352 Cloud Sept. 2, I941.

FOREIGN PA'IENTS- Number Country Date 59,604 Norway July 11, I938 

